1. Field of the Invention
The present invention relates to a photoelectric conversion element having a contact electrode for a photoelectric conversion portions and a method for manufacturing the same. More particularly, the invention relates to a photoelectric conversion element with the plurality of photoelectric conversion portions on the same substrate and a method of manufacturing the same.
2. Description of the Related Art
Today, different kinds of apparatuses such as an optical disc device, a laser beam printer, a duplicator using a laser diode, LD, have been developed. In recent years, more rapidity and higher performance are demanded for an operation provided by each of those devices. To satisfy such a demand, the use of the plurality of laser beams has been considered as one method. For example, simultaneous reading of the plurality of tracks by using the plurality of laser beams easily increase the reading speed in an optical disc device. Thus, the development of an LD, or a multi-beam laser, is demanded which can inject the plurality of laser beams simultaneously.
FIGS. 1 and 2 show the disassembled construction of a conventional. multi-beam laser. FIG. 1 shows a multi-beam laser with two laser beams. FIG. 2 shows a multi-beam laser with four laser beams. These multi-beam laser have the plurality of laser oscillators 110 on the same substrate 111. Each of those electrode 117 is electrically connected to each contact electrode 131 formed on a base 132 with each wiring 133 in between, respectively. Increase in the number of laser beams requires narrower space between each laser beam. For example, suppose the space between two laser beams is 60 xcexcm. Then, if the number of laser beams are four, the space between each laser beam will be 20 xcexcm. In this way, as the number of laser beams increases, the space S1 between each laser oscillator 110 becomes narrower.
However, in a conventional multi-beam laser, each contact electrode 131 is connected to the whole surface of each electrode 117 on each laser oscillator 110, respectively. For that reason, when the number of the laser beams increases and the space S1 between each laser oscillator 110 becomes narrower, extremely highly precise position matching has been required for those laser beams. That is, since each space between each electrode 117 and each contact electrode 131 are close, a small displacement of each contact electrode 131 makes one contact electrode 131 connect to the electrode 117 of two laser oscillators 110, respectively. Thus, each laser oscillator 110 can not be driven independently. Therefore, if the number of laser beams is increased to achieve more rapidity and higher performance, it causes difficulty in connecting each contact electrode 131 and each electrode 117 accurately. For that reason, mass production has been also difficult.
The present invention has been realized in view of such problems. It is an object of this invention to provide a photoelectric conversion element which can keep easy and accurate connection of contact electrode and a method for manufacturing the same.
The photoelectric conversion element comprises: a photoelectric conversion portion having a semiconductor layer equipped on a substrate and an electrode equipped on the semiconductor layer, a contact electrode electrically connected to the electrode of the photoelectric conversion portion, and an insulating layer formed between the contact electrode and the electrode of the photoelectric conversion portion and equipped with an opening for connecting them electrically.
The method for manufacturing the photoelectric conversion element according to this invention includes: forming a photoelectric conversion portion having a semiconductor layer equipped on a substrate and an electrode equipped on the semiconductor layer, forming an insulating layer having an opening for the electrode of the photoelectric conversion portion, and forming a contact electrode electrically connected to the electrode of the photoelectric conversion portion through the opening of the insulating layer.
In the photoelectric conversion element according to this invention, the electrode of the photoelectric conversion portion and the contact electrode are electrically connected through the opening of the insulating layer. Thus, high precision is not required for the position matching of the electrode and the contact electrode, being connected easily and accurately.
In the method for manufacturing the photoelectric conversion element according to this invention, the photoelectric conversion portion having the semiconductor layer equipped on the substrate and the electrode is formed first. Then, the insulating layer with the opening for this electrode is formed. Following that, the contact electrode is formed which is electrically connected to the electrode of the photoelectric portion through the opening of this insulating layer.